configure vlan-if jumbo mtu crashs kernel

[6bone%6bone.informatik.uni-leipzig.de@localhost]

hello,

in some networks we are working with jumbo mtu's. If I configure the mtu 
to the native interface all works fine.

ifconfig ixg1 mtu 9000 (no problem)

but

ifconfig vlan850 ip4csum tcp4csum udp4csum tcp6csum udp6csum ip4csum-tx 
ip4csum-rx tcp4csum-tx tcp4csum-rx udp4csum-tx udp4csum-rx tcp6csum-tx 
tcp6csum-rx udp6csum-tx udp6csum-rx tso4 tso6 mtu 9000

results in a kernel crash (netbsd-7):

#0  0xffffffff806867df in cpu_reboot (howto=howto@entry=260,
    bootstr=bootstr@entry=0x0) at /usr/src/sys/arch/amd64/amd64/machdep.c:671
#1  0xffffffff808cc214 in vpanic (fmt=fmt@entry=0xffffffff80dd44dd "trap",
    ap=ap@entry=0xfffffe815af29a28) at /usr/src/sys/kern/subr_prf.c:340
#2  0xffffffff808cc2cf in panic (fmt=fmt@entry=0xffffffff80dd44dd "trap")
    at /usr/src/sys/kern/subr_prf.c:256
#3  0xffffffff8091b531 in trap (frame=0xfffffe815af29b30)
    at /usr/src/sys/arch/amd64/amd64/trap.c:298
#4  0xffffffff80100fde in alltraps ()
#5  0xffffffff804c62fb in vlan_ioctl (ifp=0xfffffe8a70fc2410, cmd=2149607797,
    data=0xfffffe815af29df8) at /usr/src/sys/net/if_vlan.c:553
#6  0xffffffff803e88f5 in doifioctl (so=0xfffffe8bf6dfadb0, cmd=2149607797,
    data=<optimized out>, l=0xfffffe88032ca560) at /usr/src/sys/net/if.c:1934
#7  0xffffffff808e9976 in soo_ioctl (fp=<optimized out>, cmd=2149607797,
    data=0xfffffe815af29df8) at /usr/src/sys/kern/sys_socket.c:202
#8  0xffffffff808deb79 in sys_ioctl (l=<optimized out>,
    uap=0xfffffe815af29f00, retval=<optimized out>)
    at /usr/src/sys/kern/sys_generic.c:681
#9  0xffffffff808e9a7a in sy_call (rval=0xfffffe815af29eb8,
    uap=0xfffffe815af29f00, l=0xfffffe88032ca560,
    sy=0xffffffff810d2ba0 <sysent+864>) at /usr/src/sys/sys/syscallvar.h:61
#10 sy_invoke (code=54, rval=0xfffffe815af29eb8, uap=0xfffffe815af29f00,
    l=0xfffffe88032ca560, sy=0xffffffff810d2ba0 <sysent+864>)
    at /usr/src/sys/sys/syscallvar.h:85
#11 syscall (frame=0xfffffe815af29f00)
    at /usr/src/sys/arch/x86/x86/syscall.c:156
#12 0xffffffff80100691 in Xsyscall ()


Is is possible to get a patch so that I can use jumbo-frames with vlan 
interfaces?



Thank you for your efforts


Regards
Uwe